21537573661144 has 16 divisors (see below), whose sum is σ = 40410781753320. Its totient is φ = 10761365193600.

The previous prime is 21537573661073. The next prime is 21537573661159. The reversal of 21537573661144 is 44116637573512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 927692289 + ... + 927715504.

Almost surely, 2^{21537573661144} is an apocalyptic number.

It is an amenable number.

21537573661144 is a deficient number, since it is larger than the sum of its proper divisors (18873208092176).

21537573661144 is a wasteful number, since it uses less digits than its factorization.

21537573661144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1855409250 (or 1855409246 counting only the distinct ones).

The product of its digits is 12700800, while the sum is 55.

The spelling of 21537573661144 in words is "twenty-one trillion, five hundred thirty-seven billion, five hundred seventy-three million, six hundred sixty-one thousand, one hundred forty-four".